Arsenic contamination of drinking water poses significant health risks to millions of people worldwide. Current technologies used to clean arsenic-contaminated water have significant drawbacks, such as high cost and generation of large volumes of toxic waste. Edenspace Systems Corporation proposes to create the basis for a cost-effective phytofiltration technology using a recently identified arsenic hyperaccumulating fern to remove arsenic from drinking water to concentrations below regulatory limits. Phase I research demonstrates that the fern can rapidly reduce arsenic concentrations in a variety of source waters, achieving levels less than the new USEPA drinking water limit of 10 mug/L. Phase II research will further explore the fern's arsenic removal capability by varying such important water treatment factors as arsenic valences, water pH, dissolved minerals including iron, sulfur, sodium and calcium compounds, chlorination/fluoridation, intensity and spectrum of light, and fern size and root density. The work will culminate in a continuous process demonstration conducted in collaboration with the City of Albuquerque, New Mexico and Virginia Department of Health. The anticipated results of this research may provide the foundation for development of a solar-powered (photosynthetic) hydroponic technique that enables cost-effective, small-scale cleanup of arsenic-contaminated drinking water.